Can the regulatory actions during the boost phase of hyperbaric oxygen therapy cause Valsalva retinopathy? 1. Valsalva retinopathy: Valsalva action closes the acoustic portal, the intra-abdominal and thoracic pressure rises sharply, the venous blood return volume decreases, and the beat volume decreases, which leads to a sudden rise in peripheral venous blood pressure, and the pressure is transmitted to the eye causing the retinal capillaries to rupture and bleed. This disease is not rare clinically, but most of them have no obvious symptoms or mild symptoms; when the amount of hemorrhage is large, there is often a large internal boundary membrane detachment and sub-interior boundary membrane accumulation of blood, and it tends to occur in the macula, which can cause significant vision loss. If the patient’s hemorrhage does not absorb on its own, surgery or laser treatment may be used. The valsalva maneuver is a deep inhalation followed by a forceful expiratory maneuver for 10-15 seconds in a breath-holding state. Clinical significance of valsalva maneuver: Increase intrathoracic pressure and significantly reduce venous return; excite the vagus nerve; for example: (1) paroxysmal supraventricular tachycardia, the valsalva maneuver excites the vagus nerve to terminate an episode of supraventricular tachycardia; (2) in hypertrophic obstructive cardiomyopathy, the valsalva maneuver reduces the amount of blood return to enhance the murmur and is used to identify the murmur; (3) Mitral valve prolapse leads to mitral regurgitation, and the murmur is enhanced by valsalva maneuver. valsalva maneuver should not be too long, otherwise it will lead to the reduction of cerebral blood flow and coronary blood flow. 2. The regulating action of the pressure-raising phase during hyperbaric oxygen therapy is very critical. Repeated swallowing action or pinching and bulging action should be performed from the beginning of boosting, otherwise it will easily cause middle ear pressure injury. Valsalva retinopathy has not been seen as a result of hyperbaric oxygen boosting, and it does not occur in patients with no retinal vascular malformations or coagulation disorders. It should be noted that the regulating action is done at the beginning of boosting, and in many cases repeated swallowing means that the pressure inside and outside the inner ear has been equalized; it is recommended that the regulating action be done in short, one-at-a-time bursts, with a force that is discretionary but not very forceful.